8
The Human Population
The Science of Demography

Demography
 Science

of population structure and growth
Human Population since 1980 is J-shaped curve
© 2012 John Wiley & Sons, Inc. All rights reserved.
Human Population Growth

Human population reached:
1
billion around 1800
130 yrs
 2 billion in 1930
30 yrs
 3 billion in 1960
15 yrs
 4 billion in 1975
12 yrs
 5 billion in 1987
12 yrs
 6 billion in 1999
12 yrs
 7 billion in 2011
© 2012 John Wiley & Sons, Inc. All rights reserved.
Human Population Growth

Population is increasing due to:
 Decrease
in death rate (not increase in birth rate)
 Greater
food production
 Better medical care
 Improvements in water quality and sanitation

Growth rate (r) has started to decline
 Will
continue to decline until “zero population growth”
 When
the birth rate = death rate
 S-curve
may replace J-curve
© 2012 John Wiley & Sons, Inc. All rights reserved.
Carrying Capacity

Carrying Capacity (K)
 The
maximum number of individuals of a given
species that a particular environment can support for
an indefinite period, assuming no changes in the
environment


Both environmental constraints and human values
have an impact on K
Uncertain what the carrying capacity of the earth is
for humans
 One
est shows 4-16 billion
© 2012 John Wiley & Sons, Inc. All rights reserved.
Current & Future Population Numbers

Projections for 2050
 Low
= 7.96 billion
 High = 10.46 billion
 Most likely = 9.15 billion
© 2012 John Wiley & Sons, Inc. All rights reserved.
Demographics of Countries
© 2012 John Wiley & Sons, Inc. All rights reserved.
Demographics of Countries

Highly developed countries
 Low
rates of pop. Growth
 Lowest birth rates
 Lowest infant mortality

Less developed countries
 High
birth rates
 High infant mortality
 Short life spans
© 2012 John Wiley & Sons, Inc. All rights reserved.
Replacement Level Fertility

Number of children a couple
must have to “replace
themselves”
 2.1

children
Total fertility rate worldwide is
2.5 children
 More
than replacement level
fertility
© 2012 John Wiley & Sons, Inc. All rights reserved.
Demographic Stages

Pre-industrial Stage
 Birth

& death rates high, modest population growth
Transitional Stage
 Lowered

Industrial Stage
 Birth

death rate, rapid population growth
rate decline, population growth slow
Post Industrial Stage
 Low
birth and death rates, population growth very slow
© 2012 John Wiley & Sons, Inc. All rights reserved.
Demographic Stages
© 2012 John Wiley & Sons, Inc. All rights reserved.
Population & Quality of Life

Difficult to meet basic needs in developing countries

Problems associated with overpopulation:
 Environmental
degradation
 Hunger
 Persistent
poverty
 Economic stagnation
 Urban deterioration
 Health issues
© 2012 John Wiley & Sons, Inc. All rights reserved.
Population & Chronic Hunger

Food security
 Condition
in which people do not live with chronic
hunger and malnutrition

Effects of Chronic Hunger
 Weakened
immune system
 Illness & disease
 Malaria
 Measles
 Diarrhea
 Acute
respiratory illness
© 2012 John Wiley & Sons, Inc. All rights reserved.
Population & Chronic Hunger

Food insecurity
 Conditions
under which people live with continuous
threat of starvation

Solving the Food Problem
 Control
population growth
 Promote economic development of developing
countries without adequate food supplies
 Provide assess to food and land resources to those
who live in areas without them
 (and if you look on like there are lots more ideas)
© 2012 John Wiley & Sons, Inc. All rights reserved.
Economic Effects of Population Growth

Two viewpoints from economists:
 Population
growth stimulates economic development
and technological innovation
 Rapid population expansion hampers developmental
efforts

Most observations support the second viewpoint

In order for country to increase its standard of
living, its economic growth must exceed its
population growth
© 2012 John Wiley & Sons, Inc. All rights reserved.
Reducing the Total Fertility Rate
Three major influences on total fertility rate
1.
Cultural traditions
2.
Social & economic status of women
3.
Family planning
© 2012 John Wiley & Sons, Inc. All rights reserved.
Cultural & Fertility

Culture influences and controls
individuals’ behaviors
 Marriage
age
 Marry
young = more children
 Marry older = Less children
 Due to high infant & child mortality
rates
 couples are expected to have large
number of children
 Religious
values
 Education increases a women’s
option & dec. fertility rates
© 2012 John Wiley & Sons, Inc. All rights reserved.
Social & Economic Status of Women


Gender inequality is common worldwide
Disparities
 Political
participation
 Social status
 Economic status
 Health status
 Legal rights
 Education
 Employment & earnings
Illiteracy in 2002
Single most important factor affecting high total fertility rates is low status of
women
© 2012 John Wiley & Sons, Inc. All rights reserved.
Family Planning Services

Family planning services offer
 information
to both men and women on sexuality,
contraception, STDs, and parenting

Contraceptive used is strongly linked to lower
fertility rates
© 2012 John Wiley & Sons, Inc. All rights reserved.
Government Policy & Fertility - China

Largest population in the world

Controversial Family Planning Policy
 1971-
Chinese Gov. actively pursued birth control
 1979 - Incentives to promote later marriages &
one-child families
 Medical
care, schooling for child, preferential housing,
retirement funds
 If second child was born, all incentives had to be reimbursed
 Brought
about rapid and drastic decrease in fertility
 Decrease
in fertility from 5.8 births per woman to 2.1 birth per
woman in 1981
© 2012 John Wiley & Sons, Inc. All rights reserved.
Government Policy & Fertility- China

Plan was controversial and unpopular
 Social
pressure to abort a second child
 Pressure to abort/kill female first child
 120
boys to 100 girls as of 2000
 Plan
much more
relaxed in rural China

2011 TFR = 1.5
© 2012 John Wiley & Sons, Inc. All rights reserved.
Government Policy and Fertility- Mexico

Young age structure (More young than old)
 Huge
potential for population growth:
29% of population is under age 15
 High

Population Growth Momentum
1974 - government imparted educational reform,
family planning, health care
 Very
successful
 TFR dropped from 6.7 (1970) to 2.3 (2011)
© 2012 John Wiley & Sons, Inc. All rights reserved.
Achieving Population Stabilization

How can developing country governments help?
 Increase
$$ allotted to pubic health and family
planning services
 Education on methods of birth control
 Increase average level of education

How can developed country governments help?
 Provide
financial support
 Supporting research and development of new birth
control methods
© 2012 John Wiley & Sons, Inc. All rights reserved.